The 118-foot wingspan line: why A320s and 737s stop just short
Fourteen of the 364 types on this site have a wingspan within 2% under 118 ft, the line where Airplane Design Group IV begins. They are every A319, A320 and A321 variant (117.5 ft with sharklets), the 737-600 to 737-900 (117.4 ft with winglets), the 737 MAX 7, MAX 8 and MAX 9 (117.8 ft) and one piston airliner, the Douglas DC-6 (117.5 ft).
The closest of them, the three 737 MAX variants, stop 0.2 ft short. Above the line the file is empty for a while: no type has a wingspan between 117.8 and 124.8 ft, and the narrowest Group IV span belongs to the Antonov An-12 at 124.8 ft. Below the cluster there is a smaller gap down to the next span, 115.2 ft.
Why one line matters so much
The FAA’s Airport Design advisory circular, AC 150/5300-13B, sorts aircraft into Design Groups by wingspan and tail height, and the group is the higher of the two. Group III runs from 79 to under 118 ft of span and from 30 to under 45 ft of tail height. The circular organises its airport design standards by these groups. This explainer does not go into what any particular airport can accept; it only shows where the published dimensions fall.
Tail height never pushes these types up a group. Their tails range from 28.4 ft on the DC-6 to 41.7 ft on the 737-600, all under the 45 ft line. For the thirteen jets both dimensions land in Group III; for the DC-6 the wingspan alone sets it.
Winglets and sharklets close the gap to 118 ft
What the wingtip devices add
For seven of the fourteen the FAA file lists two spans. The 737-600, -700, -800 and -900 measure 112.6 ft without winglets and 117.4 ft with them, a gain of 4.8 ft. The A319, A320 and A321 grow from 111.9 ft to 117.5 ft with sharklets, 5.6 ft more. In both lines the larger figure still leaves 0.6 ft or less to the line. The three neo variants and the three MAX variants appear in the file with a single span.
This site ranks and classifies every type by the larger of its two spans, so the figures above are the ones that decide the group.
Same span, very different lengths
A shared span does not mean a shared length. Within the fourteen, length runs from 100.6 ft on the DC-6 to 146.0 ft on the A321 and A321neo, a difference of 45.4 ft. Among the jets the range starts at 102.5 ft on the 737-600. Both lines cover a wide length range while their wings stay inside the group, and the 737 and A320 comparison takes those length ranges variant by variant.
| Type | Wingspan | Under 118 ft by | Length | US flight-plan operations, FY2024 |
|---|---|---|---|---|
| Boeing 737 MAX 7 | 117.8 ft | 0.2 ft | 116.7 ft | 94 |
| Boeing 737 MAX 8 | 117.8 ft | 0.2 ft | 129.7 ft | 1,020,032 |
| Boeing 737 MAX 9 | 117.8 ft | 0.2 ft | 138.3 ft | 291,234 |
| Douglas DC-6 | 117.5 ft | 0.5 ft | 100.6 ft | 1,644 |
| Airbus A319 | 117.5 ft | 0.5 ft | 111.0 ft | 915,976 |
| Airbus A319neo | 117.5 ft | 0.5 ft | 111.0 ft | 166 |
| Airbus A320 | 117.5 ft | 0.5 ft | 123.3 ft | 1,397,404 |
| Airbus A320neo | 117.5 ft | 0.5 ft | 123.3 ft | 540,276 |
| Airbus A321 | 117.5 ft | 0.5 ft | 146.0 ft | 1,364,686 |
| Airbus A321neo | 117.5 ft | 0.5 ft | 146.0 ft | 307,984 |
| Boeing 737-600 | 117.4 ft | 0.6 ft | 102.5 ft | 16,720 |
| Boeing 737-700 | 117.4 ft | 0.6 ft | 110.3 ft | 1,720,060 |
| Boeing 737-800 | 117.4 ft | 0.6 ft | 129.5 ft | 2,484,764 |
| Boeing 737-900 | 117.4 ft | 0.6 ft | 138.2 ft | 962,126 |
The neighbours on either side
Below the cluster the next spans belong to the Embraer E195-E2, Airbus A220-100 and Airbus A220-300, between 2.8 and 2.9 ft under the line and so outside the 2% window. Above it, Group IV opens with the Antonov An-12 at 124.8 ft, the Boeing KC-135 Stratotanker at 130.8 ft, the Transall C-160 at 131.2 ft and the Lockheed C-130 Hercules at 132.6 ft.
Weight inside the fourteen varies more than span does. The DC-6 has the lowest published maximum takeoff weight of the group at 107,000 lb; the A321neo has the highest at 209,439 lb.
The same span also hides a spread of approach categories. By the FAA reference approach speed, the input for that code, the fourteen split into 1 in Category B, 7 in Category C and 6 in Category D. Six of them are among the twelve types the FAA lists in both C and D, so the FAA gives a range of reference speeds for them rather than a single figure. The approach category explainer covers those twelve.
How much traffic sits near the line
The FAA file also carries a count of US flight-plan operations for fiscal year 2024. Of the 30,307,278 operations counted across the 352 types with a count, 11,023,166, or 36.4%, were flown by these fourteen types. That share covers only flights with a US flight plan, which under-counts piston aircraft, and it says nothing about traffic outside the United States.
The size overlay uses a box of 118 × 130 × 42 ft as its default for that reason: the A320 and the 737-800 both fall inside it.
Sources: FAA Aircraft Characteristics Database, October 2024 release (wingspans with and without winglets, lengths, tail heights at operating empty weight, FY2024 US flight-plan operations); FAA Advisory Circular 150/5300-13B, Table 1-2. Margins and shares computed by this site.